Imperial College London

Professor Camille Petit

Faculty of EngineeringDepartment of Chemical Engineering

Professor of Materials Engineering
 
 
 
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Contact

 

camille.petit Website

 
 
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Location

 

506ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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146 results found

Low M-YA, Danaci D, Azzan H, Woodward RT, Petit Cet al., 2023, Measurement of physicochemical properties and CO2, N2, Ar, O2, and H2O unary adsorption isotherms of Purolite A110 and Lewatit VP OC 1065 for application in direct air capture, Journal of Chemical and Engineering Data, Vol: 68, Pages: 3499-3511, ISSN: 0021-9568

Direct air capture (DAC) using solid adsorbents has gained significant attention as a carbon dioxide removal (CDR) technology to help limit global temperature rise to below 2 °C. One large area of focus is the development of new adsorbent materials for DAC. However, the necessary data needed to employ these materials in process models for adsorbent screening are rarely available. Here, we showcase Purolite A110, a commercially available amine-functionalized polymeric resin, as a new candidate adsorbent for DAC and compare its properties to a current benchmark, Lewatit VP OC 1065. For both materials, we report their chemical features and composition, skeletal, particle, and bed density, total pore volume, particle porosity, BET area, thermal stability, and specific heat capacity. We determine their equilibrium sorption properties by measuring the volumetric CO2 isotherms at 288, 298, 308, 333, 343, 353, and 393 K, N2 and H2O isotherms at 288, 298, and 308 K, and Ar and O2 isotherms at 298 K. For CO2, N2, and H2O, we also present the corresponding isotherm model fitting parameters and heats of adsorption. These data can help facilitate process modeling and optimization studies to properly assess these adsorbents at scale.

Journal article

Azzan H, Danaci D, Petit C, Pini Ret al., 2023, Unary adsorption equilibria of hydrogen, nitrogen and carbon dioxide on y-type zeolites at temperatures from 298 to 393 k and at pressures up to 3 MPA, Journal of Chemical and Engineering Data, Vol: 68, Pages: 3512-3524, ISSN: 0021-9568

The equilibrium adsorption of CO2, N2, and H2 on commercially available Zeolite H–Y, Na–Y, and cation-exchanged NaTMA–Y was measured up to 3 MPa at 298.15, 313.15, 333.15, 353.15, and 393.15 K gravimetrically using a magnetic suspension balance. The chemical and textural characterization of the materials was carried out by thermogravimetric analysis, helium gravimetry, and N2 (77 K) physisorption. We report the excess and net isotherms as measured and estimates of the absolute adsorption isotherms. The latter are modeled using the simplified statistical isotherm (SSI) model to evaluate adsorbate–adsorbent interactions and parametrize the data for process modeling. When reported per unit volume of zeolite supercage, the SSI model indicates that the saturation capacity for a given gas takes the same value for the three adsorbents. The Henry’s constants predicted by the model show a strong effect of the cation on the affinity of each adsorbate.

Journal article

Danaci D, Pulidori E, Bernazzani L, Petit C, Taddei Met al., 2023, Evaluating the CO2 capture performance of a “phase-change” metal-organic framework in a pressure-vacuum swing adsorption process, Molecular Systems Design & Engineering, Vol: 8, Pages: 1526-1539, ISSN: 2058-9689

Metal–organic frameworks (MOFs) that display step-shaped adsorption isotherms, i.e., “phase-change” MOFs, represent a relatively small subset of all known MOFs. Yet, they are rapidly emerging as promising sorbents to achieve excellent gas separation performances with little energy demand. In this work, we assessed F4_MIL-140A(Ce), a recently discovered “phase-change” MOF adsorbent, for CO2 capture in two scenarios using a pressure-vacuum swing adsorption process, namely a coal-fired power plant flue gas (12.5%mol CO2), and a steel plant flue gas (25.5%mol CO2). Four CO2 and three N2 adsorption isotherms were collected on F4_MIL-140A(Ce) over a range of temperatures and modelled using a bespoke equation for step-shaped isotherms. We accurately measured the heat capacity of F4_MIL-140A(Ce), a key thermodynamic property for a sorbent, using a method based on differential scanning calorimetry that overcomes the issues associated with the poor thermal conductivity of MOF powders. We then used these experimental data as input in a process optimisation framework and we compared the CO2 capture performance of F4_MIL-140A(Ce) to that of other “canonical” sorbents, including, zeolite 13X, activated carbon and three MOFs (i.e., HKUST-1, UTSA-16 and CALF-20). We found that F4_MIL-140A(Ce) has the potential to perform better than other sorbents, in terms of recovery and purity, under most of the simulated process conditions. We attribute such promising performance to the non-hysteretic step-shaped isotherm, the low uptake capacity for N2 and the mild heat of CO2 adsorption displayed by F4_MIL-140A(Ce).

Journal article

Pedersen A, Pandya J, Leonzio G, Serov A, Bernardi A, Stephens IEL, Titirici MM, Petit C, Chachuat Bet al., 2023, Comparative techno-economic and life-cycle analysis of precious versus non-precious metal electrocatalysts: the case of PEM fuel cell cathodes, Green Chemistry, Vol: 25, Pages: 10458-10471, ISSN: 1463-9262

Sluggish kinetics in the oxygen reduction reaction (ORR) require significant quantities of expensive Pt-based nanoparticles on carbon (Pt/C) at the cathode of proton exchange membrane fuel cells (PEMFCs). This catalyst requirement hinders their large-scale implementation. Single atom Fe in N-doped C (Fe-N-C) electrocatalysts offer the best non-Pt-based ORR activities to date, but their environmental impacts have not been studied and their production costs are rarely quantified. Herein, we report a comparative life-cycle assessment and techno-economic analysis of replacing Pt/C with Fe-N-C at the cathode of an 80 kW PEMFC stack. In the baseline scenario (20 gPt/Cvs. 690 gFe-N-C), we estimate that Fe-N-C could reduce damages on ecosystems and human health by 88-90% and 30-44%, respectively, while still increasing global warming potential by 53-92% and causing a comparable impact on resource depletion. The environmental impacts of Pt/C predominantly arise from the Pt precursor while those of Fe-N-C are presently dominated by the electricity consumption. The monetized costs of environmental externalities for both Fe-N-C and Pt/C catalysts exceed their respective direct production costs. Based on catalyst performance with learning curve analysis at 500 000 PEMFC stacks per annum, we estimate replacing Pt/C with Fe-N-C would increase PEMFC stack cost from 13.8 to 41.6 USD per kW. The cost increases despite a reduction in cathode catalyst production cost from 3.41 to 0.79 USD per kW (excluding environmental externalities). To be cost-competitive with a Pt-based PEMFC stack delivering 2020 US Department of Energy target of 1160 mW cm−2 (at 0.657 V), the same stack with an Fe-N-C cathode would need to reach 874 mW cm−2, equivalent to a 200% performance improvement. These findings demonstrate the need for continued Fe-N-C activity development with sustainable synthesis routes in mind to replace Pt-based cathode catalyst in PEMFCs. Based on forecasting scenarios of

Journal article

Nguyen HGT, Toman B, van Zee RD, Prinz C, Thommes M, Ahmad R, Kiska D, Salinger J, Walton IM, Walton KS, Broom DP, Benham MJ, Ansari H, Pini R, Petit C, Adolphs J, Schreiber A, Shigeoka T, Konishi Y, Nakai K, Henninger M, Petrzik T, Kececi C, Martis V, Paschke T, Mangano E, Brandani Set al., 2023, Reference isotherms for water vapor sorption on nanoporous carbon: results of an interlaboratory study, Adsorption, Vol: 29, Pages: 113-124, ISSN: 0929-5607

This paper reports the results of an international interlaboratory study sponsored by the Versailles Project on Advanced Materials and Standards (VAMAS) and led by the National Institute of Standards and Technology (NIST) on the measurement of water vapor sorption isotherms at 25 °C on a pelletized nanoporous carbon (BAM-P109, a certified reference material). Thirteen laboratories participated in the study and contributed nine pure water vapor isotherms and four relative humidity isotherms, using nitrogen as the carrier gas. From these data, reference isotherms, along with the 95% uncertainty interval (Uk=2), were determined and are reported in a tabular format.

Journal article

L'Hermitte A, Azzan H, Yio MHN, Rajagopalan AK, Danaci D, Hirosawa T, Isobe T, Petit Cet al., 2023, Effect of surface functionalization on the moisture stability and sorption properties of porous boron nitride, Microporous and Mesoporous Materials, Vol: 352, Pages: 1-13, ISSN: 1387-1811

Porous boron nitride (BN) is a promising adsorbent owing to its high surface area and porosity, as well as thermal and oxidative stability. It has been explored in the past decade for applications in gas and liquid separations, such as CO2 capture and water cleaning. However, the material has displayed hydrolytic instability. Owing to the presence of moisture in most industrial settings, whether it is for storage or cyclic adsorption processes, ensuring the moisture stability of an adsorbent is crucial. While this topic has been researched for other adsorbents such as zeolites and metal organic frameworks (MOFs), little is known on controlling the hydrolytic stability of porous BN. In this study, we propose a method to enhance porous BN's hydrolytic stability via surface functionalization using a fluoroalkylsilane. We explored two different routes of functionalization: (i) functionalization of porous BN powder followed by pelletization (route 1) and (ii) coating of porous BN pellets with fluoroalkylsilane (route 2). Spectroscopic, analytical and imaging techniques confirmed the functionalization process qualitatively and quantitatively. We subjected the functionalized samples to moisture exposure at 54% RH (similar to common storage conditions) and 92% RH (similar to flue gas stream conditions with high moisture content), and characterized them to probe their resistance to moisture. We also investigated their equilibrium and kinetic sorption properties in the context of CO2/N2 separation. Both routes produced materials with enhanced moisture stability. However, we noted differences between both functionalization routes. Route 2 produced a sample with a higher grafting yield and hydrophobic nature, and therefore better resistance to moisture exposure than route 1. From a sorption point of view, despite reduced porosity, the functionalized samples maintain reasonable CO2 uptakes. The functionalization led to changes in the textural features of the samples, which cause

Journal article

Mistry EDR, Lubert-Perquel D, Nevjestic I, Mallia G, Ferrer P, Roy K, Held G, Tian T, Harrison NM, Heutz S, Petit Cet al., 2023, Paramagnetic states in oxygen-doped boron nitride extend light harvesting and photochemistry to the deep visible region, Chemistry of Materials, Vol: 35, Pages: 1858-1867, ISSN: 0897-4756

A family of boron nitride (BN)-based photocatalysts for solar fuel syntheses have recently emerged. Studies have shown that oxygen doping, leading to boron oxynitride (BNO), can extend light absorption to the visible range. However, the fundamental question surrounding the origin of enhanced light harvesting and the role of specific chemical states of oxygen in BNO photochemistry remains unanswered. Here, using an integrated experimental and first-principles-based computational approach, we demonstrate that paramagnetic isolated OB3 states are paramount to inducing prominent red-shifted light absorption. Conversely, we highlight the diamagnetic nature of O–B–O states, which are shown to cause undesired larger band gaps and impaired photochemistry. This study elucidates the importance of paramagnetism in BNO semiconductors and provides fundamental insight into its photophysics. The work herein paves the way for tailoring of its optoelectronic and photochemical properties for solar fuel synthesis.

Journal article

Itskou I, L'Hermitte A, Marchesini S, Tian T, Petit Cet al., 2023, How to Tailor Porous Boron Nitride Properties for Applications in Interfacial Processes, ACCOUNTS OF MATERIALS RESEARCH

Journal article

Low M-YA, Barton LV, Pini R, Petit Cet al., 2023, Analytical review of the current state of knowledge of adsorption materials and processes for direct air capture, Chemical Engineering Research and Design, Vol: 189, Pages: 745-767, ISSN: 0263-8762

Significant research interest has been directed towards the deployment of direct air capture (DAC) as a net-negative CO2 emissions technology to help limit global temperature rise to below 2 °C. The scope of this review is to outline the advancement of adsorption-based DAC technologies, as well as to highlight the still-existing data gaps, for both materials’ development and process design in the period 2016 – 2021. On the material side, we highlight the available and missing data on adsorbent properties in relation to what is needed for process modelling and design. We cover material densities, textural properties, thermal properties, adsorption isotherms (i.e. CO2, N2, O2, H2O), adsorption kinetics, and adsorbent stability towards humidity, oxidation, and cycling. On the process side, we provide a detailed look at key process studies conducted in the same time frame by considering the trade-offs to be expected in the design of the adsorption-based DAC process. We focus on process configuration and contactor design, desorption processes, and the need for systematic reporting of key performance indicators to allow for accurate comparisons and benchmarking. Throughout the review, we identify the lack of synergy between material and process development which must be addressed to advance the field of DAC by adsorption.

Journal article

Xiong Y, Tian T, L'Hermitte A, Mendez ASJ, Danaci D, Platero-Prats AE, Petit Cet al., 2022, Using silver exchange to achieve high uptake and selectivity for propylene/ propane separation in zeolite Y, Chemical Engineering Journal, Vol: 446, ISSN: 1385-8947

Adsorptive separation of propylene and propane, an important step of polypropylene production, is more energy-efficient than distillation. However, the challenge lies in the design of an adsorbent which exhibits both high selectivity and uptake. Herein, we hypothesise that enhancing the propylene affinity of the adsorption sites while keeping a suitable pore size can address this challenge. To do so, we performed silver exchange of a commercial zeolite Y, thereby making the adsorbent design easily scalable. We characterised the adsorbent using analytical, spectroscopic and imaging tools, tested its equilibrium and dynamic sorption properties using volumetric and gravimetric techniques and compared its performance to those of state-of-the-art adsorbents as well as other silver-functionalised adsorbents. The silver-exchanged zeolite Y (Ag-Y) exhibited one of the best selectivity vs uptake performances reported so far. Ag-Y also displayed fast adsorption kinetics and reversible propylene sorption, making it a promising new benchmark for propylene/propane separation. Synchrotron-based pair distribution function analyses identified the silver cations’ location which confirmed that the silver sites are easily accessible to the adsorbates. This aspect can, in part, explain the propylene/propane separation performance observed. The overall design strategy proposed here to enhance sorption site affinity and maintain pore size could be extended to other adsorbents and support the deployment of adsorption technology for propylene/propane separation.

Journal article

Schukraft GEM, Itskou I, Woodward RT, Linden BVD, Petit C, Urakawa Aet al., 2022, Evaluation of CO2 and H2O Adsorption on a Porous Polymer Using DFT and In Situ DRIFT Spectroscopy, JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 126, Pages: 8048-8057, ISSN: 1520-6106

Journal article

Tian T, Xu J, Xiong Y, Ramanan N, Ryan M, Xie F, Petit Cet al., 2022, Cu-functionalised porous boron nitride derived from a metal–organic framework, Journal of Materials Chemistry A, Vol: 10, Pages: 20580-20592, ISSN: 2050-7488

Porous boron nitride (BN) displays promising properties for interfacial and bulk processes, e.g. molecular separation and storage, or (photo)catalysis. To maximise porous BN's potential in such applications, tuning and controlling its chemical and structural features is key. Functionalisation of porous BN with metal nanoparticle represents one possible route, albeit a hardly explored one. Metal–organic frameworks (MOFs) have been widely used as precursors to synthesise metal functionalised porous carbon-based materials, yet MOF-derived metal functionalised inorganic porous materials remain unexplored. Here, we hypothesise that MOFs could also serve as a platform to produce metal-functionalised porous BN. We have used a Cu-containing MOF, i.e. Cu/ZIF-8, as a precursor and successfully obtained porous BN functionalised with Cu nanoparticles (i.e. Cu/BN). While we have shown control of the Cu content, we have not yet demonstrated it for the nanoparticle size. The functionalisation has led to improved light harvesting and enhanced electron–hole separation, which have had a direct positive impact on the CO2 photoreduction activity (production formation rate 1.5 times higher than pristine BN and 12.5 times higher than g-C3N4). In addition, we have found that the metal in the MOF precursor impacts porous BN's purity. Unlike Cu/ZIF-8, a Co-containing ZIF-8 precursor led to porous C-BN (i.e. BN with a large amount of C in the structure). Overall, given the diversity of metals in MOFs, one could envision our approach as a method to produce a library of different metal functionalised porous BN samples.

Journal article

Taddei M, Petit C, 2022, Engineering metal-organic frameworks for adsorption-based gas separations: from process to atomic scale (vol 6, pg 841, 2021), MOLECULAR SYSTEMS DESIGN & ENGINEERING, Vol: 7, Pages: 1162-1162, ISSN: 2058-9689

Journal article

Azzan H, Rajagopalan AK, L'Hermitte A, Pini R, Petit Cet al., 2022, Simultaneous estimation of gas adsorption equilibria and kinetics of individual shaped adsorbents, Chemistry of Materials, Vol: 34, Pages: 6671-6686, ISSN: 0897-4756

Shaped adsorbents (e.g., pellets, extrudates) are typically employed in several gas separation and sensing applications. The performance of these adsorbents is dictated by two key factors, their adsorption equilibrium capacity and kinetics. Often, adsorption equilibrium and textural properties are reported for materials. Adsorption kinetics are seldom presented due to the challenges associated with measuring them. The overarching goal of this work is to develop an approach to characterize the adsorption properties of individual shaped adsorbents with less than 100 mg of material. To this aim, we have developed an experimental dynamic sorption setup and complemented it with mathematical models, to describe the mass transport in the system. We embed these models into a derivative-free optimizer to predict model parameters for adsorption equilibrium and kinetics. We evaluate and independently validate the performance of our approach on three adsorbents that exhibit differences in their chemistry, synthesis, formulation, and textural properties. Further, we test the robustness of our mathematical framework using a digital twin. We show that the framework can rapidly (i.e., in a few hours) and quantitatively characterize adsorption properties at a milligram scale, making it suitable for the screening of novel porous materials.

Journal article

Xiao F-S, Azevedo D, Nicholas CP, Petit Cet al., 2022, Preface for Special Issue on Engineered Methodologies for CO<sub>2</sub> Utilization, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 61, Pages: 10295-10297, ISSN: 0888-5885

Journal article

Hwang J, Azzan H, Pini R, Petit Cet al., 2022, H2, N2, CO2, and CH4 unary adsorption isotherm measurements at low and high pressures on zeolitic imidazolate framework ZIF-8, Journal of Chemical &amp; Engineering Data, Vol: 67, Pages: 1674-1686, ISSN: 0021-9568

Excess adsorption of CO2, CH4, N2, and H2 on ZIF-8 was measured gravimetrically in the pressure range ranging from vacuum to 30 MPa at 298.15, 313.15, 333.15, 353.15, and 394.15 K using a magnetic suspension balance. The textural properties of the adsorbent material─i.e., skeletal density, surface area, pore volume, and pore-size distribution─were estimated by helium gravimetry and N2 (77 K) physisorption. The adsorption isotherms were fitted with the Sips isotherm model and the virial equation, and the values of isosteric heat of adsorption and Henry constants for the gases were determined using the latter.

Journal article

Osterrieth JWM, Rampersad J, Madden D, Rampal N, Skoric L, Connolly B, Allendorf MD, Stavila V, Snider JL, Ameloot R, Marreiros J, Ania C, Azevedo D, Vilarrasa-Garcia E, Santos BF, Bu X-H, Chang Z, Bunzen H, Champness NR, Griffin SL, Chen B, Lin R-B, Coasne B, Cohen S, Moreton JC, Colon YJ, Chen L, Clowes R, Coudert F-X, Cui Y, Hou B, D'Alessandro DM, Doheny PW, Dinca M, Sun C, Doonan C, Huxley MT, Evans JD, Falcaro P, Ricco R, Farha O, Idrees KB, Islamoglu T, Feng P, Yang H, Forgan RS, Bara D, Furukawa S, Sanchez E, Gascon J, Telalovic S, Ghosh SK, Mukherjee S, Hill MR, Sadiq MM, Horcajada P, Salcedo-Abraira P, Kaneko K, Kukobat R, Kenvin J, Keskin S, Kitagawa S, Otake K-I, Lively RP, DeWitt SJA, Llewellyn P, Lotsch B, Emmerling ST, Putz AM, Marti-Gastaldo C, Padial NM, Garcia-Martinez J, Linares N, Maspoch D, del Pino JAS, Moghadam P, Oktavian R, Morris RE, Wheatley PS, Navarro J, Petit C, Danaci D, Rosseinsky MJ, Katsoulidis AP, Schroder M, Han X, Yang S, Serre C, Mouchaham G, Sholl DS, Thyagarajan R, Siderius D, Snurr RQ, Goncalves RB, Telfer S, Lee SJ, Ting VP, Rowlandson JL, Uemura T, Liyuka T, van derVeen MA, Rega D, Van Speybroeck V, Rogge SMJ, Lamaire A, Walton KS, Bingel LW, Wuttke S, Andreo J, Yaghi O, Zhang B, Yavuz CT, Nguyen TS, Zamora F, Montoro C, Zhou H, Kirchon A, Fairen-Jimenez Det al., 2022, How reproducible are surface areas calculated from the BET equation?, Advanced Materials, Vol: 34, ISSN: 0935-9648

Porosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer–Emmett–Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already-measured raw adsorption isotherms were provided to sixty-one labs, who were asked to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called “BET surface identification” (BETSI), expands on the well-known Rouquerol criteria and makes an unambiguous BET area assignment possible.

Journal article

Shankar RB, Mistry EDR, Lubert-Perquel D, Nevjestic I, Heutz S, Petit Cet al., 2022, A response surface model to predict and experimentally tune the chemical, magnetic and optoelectronic properties of oxygen-doped boron nitride, ChemPhysChem: a European journal of chemical physics and physical chemistry, Vol: 23, ISSN: 1439-4235

Porous boron nitride (BN), a combination of hexagonal, turbostratic and amorphous BN, has emerged as a new platform photocatalyst. Yet, this material lacks photoactivity under visible light. Theoretical studies predict that tuning the oxygen content in oxygen-doped BN (BNO) could lower the band gap. This is yet to be verified experimentally. We present herein a systematic experimental route to simultaneously tune BNO's chemical, magnetic and optoelectronic properties using a multivariate synthesis parameter space. We report deep visible range band gaps (1.50–2.90 eV) and tuning of the oxygen (2–14 at.%) and specific paramagnetic OB3 contents (7–294 a.u. g−1). Through designing a response surface via a design of experiments (DOE) process, we have identified synthesis parameters influencing BNO's chemical, magnetic and optoelectronic properties. We also present model prediction equations relating these properties to the synthesis parameter space that we have validated experimentally. This methodology can help tailor and optimise BN materials for heterogeneous photocatalysis.

Journal article

Schukraft GEM, Moss B, Kafizas AG, Petit Cet al., 2022, Effect of band bending in photoactive MOF-based heterojunctions., ACS Applied Materials and Interfaces, Vol: 14, Pages: 19342-19352, ISSN: 1944-8244

Semiconductor/metal-organic framework (MOF) heterojunctions have demonstrated promising performance for the photoconversion of CO2 into value-added chemicals. To further improve performance, we must understand better the factors which govern charge transfer across the heterojunction interface. However, the effects of interfacial electric fields, which can drive or hinder electron flow, are not commonly investigated in MOF-based heterojunctions. In this study, we highlight the importance of interfacial band bending using two carbon nitride/MOF heterojunctions with either Co-ZIF-L or Ti-MIL-125-NH2. Direct measurement of the electronic structures using X-ray photoelectron spectroscopy (XPS), work function, valence band, and band gap measurements led to the construction of a simple band model at the heterojunction interface. This model, based on the heterojunction components and band bending, enabled us to rationalize the photocatalytic enhancements and losses observed in MOF-based heterojunctions. Using the insight gained from a promising band bending diagram, we developed a Type II carbon nitride/MOF heterojunction with a 2-fold enhanced CO2 photoreduction activity compared to the physical mixture.

Journal article

Heiba HF, Bullen JC, Kafizas A, Petit C, Skinner SJ, Weiss Det al., 2022, The determination of oxidation rates and quantum yields during the photocatalytic oxidation of As(III) over TiO2, Journal of Photochemistry and Photobiology A: Chemistry, Vol: 424, Pages: 113628-113628, ISSN: 1010-6030

The determination of reaction rates for the photocatalytic oxidation (PCO) of arsenite (As(III)) using TiO2 under UV radiation is challenging due to the numerous experimental processes. This includes chemical processes running simultaneously with PCO (e.g. adsorption of arsenic species, direct UV photolysis of As(III)) and the analytical approach used (e.g. whether As(III) or As(V) are measured and used in the calculation of the PCO rate). The various experimental approaches used to date have led to oxidation rates and rate constants which vary by orders of magnitude and contradicting information on rate laws. Here we present the results of a critical examination of possible controls affecting the experimental determination of PCO rates. First, we demonstrate that the choice of analytical technique is not critical, provided that the rate constants are calculated based on the depletion of As(III) after correction of the directly adsorbed As(III). Second, we show the correction of the directly adsorbed As(III) at each time interval is best done by running two parallel experiments (one under UV and the other in dark) instead of running sequential experiment (i.e. running the experiment in the dark then turning on the UV lamp). These findings are supported by XPS analysis of the oxidation state of TiO2-sorbed As. Third, we demonstrate that photolysis by the light source itself, as well as the chemical composition of the solution (i.e. the effect of HEPES and the ionic strength), can significantly increase As(III) oxidation rates and need to be corrected. Finally, to determine the quantum yield of As(III) oxidation, we measured the photon absorption by the TiO2 photocatalyst. Our results showed that the quantum yield (Ø) for this oxidation reaction was low, and in the region of 0.1 to 0.2 %.

Journal article

Petit C, L'Hermitte A, Dawson D, Ferrer P, Roy K, Held G, Tian T, Ashbrook Set al., 2021, Formation mechanism and porosity development in porous boron nitride, The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter, Vol: 125, Pages: 27429-27439, ISSN: 1932-7447

Porous boron nitride (BN) has proven promising as a novel class of inorganic materials in the field of separations and particularly adsorption. Owing to its high surface area and thermal stability, porous BN has been researched for CO2 capture and water cleaning, for instance. However, research remains at the laboratory scale due to a lack of understanding of the formation mechanism of porous BN, which is largely a “black box” and prevents scale up. Partial reaction pathways have been unveiled, but they omit critical steps in the formation, including the porosity development, which is key to adsorption. To unlock the potential of porous BN at a larger scale, we have investigated its formation from the perspective of both chemical formation and porosity development. We have characterized reaction intermediates obtained at different temperatures with a range of analytical and spectroscopic tools. Using these analyses, we propose a mechanism highlighting the key stages of BN formation, including intermediates and gaseous species formed in the process. We identified the crucial formation of nonporous carbon nitride to form porous BN with release of porogens, such as CO2. This work paves the way for the use of porous BN at an industrial level for gas and liquid separations.

Journal article

Shankar R, Mistry E, Lubert-Perquel D, Nevjestic I, Heutz S, Petit Cet al., 2021, A response surface model to predict and experimentally tune the chemical, magnetic and optoelectronic properties of oxygen-doped boron nitride

<jats:p>A new material platform for boron nitride (BN) as a heterogeneous photocatalyst for solar fuels synthesis has recently emerged. One of the bottlenecks of this material is the lack of photoactivity under visible light, which hinders its rate performance. Theoretical studies have predicted that tuning the oxygen content in oxygen-doped BN (BNO) might be used to lower and vary the band gap. However, this is yet to be verified experimentally. We present herein a systematic experimental route facilitating simultaneous tuning of the chemical, magnetic and optoelectronic properties of BNO using a multivariate synthesis parameter space. Deep visible range band gaps (1.50 – 2.90 eV) were experimentally achieved and tuned over an oxygen composition of 2 – 14 at. %, and specific paramagnetic OB3 content of 7 – 294 a.u. g-1, thus supporting theoretical predictions. Through designing a response surface via a design of experiments (DOE) process, the key synthesis parameters influencing the chemical, magnetic and optoelectronic properties of BNO were identified. In addition, model prediction equations relating the aforementioned properties to the synthesis parameter space are presented. Accurate model predictions for the oxygen content and band gap were conducted and validated experimentally. Such a methodology is valuable for further advances in tailoring and optimising BN materials for heterogeneous photocatalytic reactions.</jats:p>

Journal article

Shankar R, Mistry E, Lubert-Perquel D, Nevjestic I, Heutz S, Petit Cet al., 2021, A response surface model to predict and experimentally tune the chemical, magnetic and optoelectronic properties of oxygen-doped boron nitride

<jats:p>A new material platform for boron nitride (BN) as a heterogeneous photocatalyst for solar fuels synthesis has recently emerged. One of the bottlenecks of this material is the lack of photoactivity under visible light, which hinders its rate performance. Theoretical studies have predicted that tuning the oxygen content in oxygen-doped BN (BNO) might be used to lower and vary the band gap. However, this is yet to be verified experimentally. We present herein a systematic experimental route facilitating simultaneous tuning of the chemical, magnetic and optoelectronic properties of BNO using a multivariate synthesis parameter space. Deep visible range band gaps (1.50 – 2.90 eV) were experimentally achieved and tuned over an oxygen composition of 2 – 14 at. %, and specific paramagnetic OB3 content of 7 – 294 a.u. g-1, thus supporting theoretical predictions. Through designing a response surface via a design of experiments (DOE) process, the key synthesis parameters influencing the chemical, magnetic and optoelectronic properties of BNO were identified. In addition, model prediction equations relating the aforementioned properties to the synthesis parameter space are presented. Accurate model predictions for the oxygen content and band gap were conducted and validated experimentally. Such a methodology is valuable for further advances in tailoring and optimising BN materials for heterogeneous photocatalytic reactions.</jats:p>

Journal article

Rajagopalan AK, Petit C, 2021, Material Screening for Gas Sensing Using an Electronic Nose: Gas Sorption Thermodynamic and Kinetic Considerations, ACS SENSORS, Vol: 6, Pages: 3808-3821, ISSN: 2379-3694

Journal article

Butler EL, Reid B, Luckham PF, Guldin S, Livingston AG, Petit Cet al., 2021, Interparticle Forces of a Native and Encapsulated Metal-Organic Framework and Their Effects on Colloidal Dispersion, ACS APPLIED MATERIALS & INTERFACES, Vol: 13, Pages: 45898-45906, ISSN: 1944-8244

Journal article

Rampal N, Ajenifuja A, Tao A, Balzer C, Cummings MS, Evans A, Bueno-Perez R, Law DJ, Bolton LW, Petit C, Siperstein F, Attfield MP, Jobson M, Moghadam PZ, Fairen-Jimenez Det al., 2021, The development of a comprehensive toolbox based on multi-level, high-throughput screening of MOFs for CO/N<sub>2</sub> separations, CHEMICAL SCIENCE, Vol: 12, Pages: 12068-12081, ISSN: 2041-6520

Journal article

Taddei M, Petit C, 2021, Engineering metal-organic frameworks for adsorption-based gas separations: from process to atomic scale, Molecular Systems Design & Engineering, Vol: 6, Pages: 841-875, ISSN: 2058-9689

Metal-organic frameworks (MOFs) are the object of intense research targeting their deployment as adsorbents for a wide range of gas separations, such as CO2 capture, biogas upgrading, air separation and small hydrocarbons separation. The scope of this review is to provide chemists, material scientists and engineers with an overview of the state-of-the-art and of the main challenges in the field of adsorption-based gas separations using MOFs. To do so, we first discuss current gas separation challenges for which adsorption could play a role. The following three sections of the paper describe process-level considerations in the design, selection and deployment of MOFs as sorbents and subsequently focus on material-level considerations. Both the process and the material aspects cover experimental and computational work. Going from the process scale to the atomic scale, we aim to highlight the links and synergies between the two and identify the current barriers that hamper the development of adsorption-based gas separations using MOFs as sorbents. Throughout the article, we also provide fundamental and technical information related to MOFs design, synthesis, characterisation and sorption testing.

Journal article

Xiong Y, Woodward RT, Danaci D, Evans A, Tian T, Azzan H, Ardakani M, Petit Cet al., 2021, Understanding trade-offs in adsorption capacity, selectivity and kinetics for propylene/propane separation using composites of activated carbon and hypercrosslinked polymer, CHEMICAL ENGINEERING JOURNAL, Vol: 426, ISSN: 1385-8947

Journal article

Danaci D, Bui M, Petit C, Mac Dowell Net al., 2021, En route to zerio emissions for power and industry with amine-based post-combustion capture, Environmental Science and Technology (Washington), Vol: 55, Pages: 10619-10632, ISSN: 0013-936X

As more countries commit to a net-zero GHG emission target, we need a whole energy and industrial system approach to decarbonization rather than focus on individual emitters. This paper presents a techno-economic analysis of monoethanolamine-based post-combustion capture to explore opportunities over a diverse range of power and industrial applications. The following ranges were investigated: feed gas flow rate between 1–1000 kg ·s–1, gas CO2 concentrations of 2–42%mol, capture rates of 70–99%, and interest rates of 2–20%. The economies of scale are evident when the flue gas flow rate is <20 kg ·s–1 and gas concentration is below 20%mol CO2. In most cases, increasing the capture rate from 90 to 95% has a negligible impact on capture cost, thereby reducing CO2 emissions at virtually no additional cost. The majority of the investigated space has an operating cost fraction above 50%. In these instances, reducing the cost of capital (i.e., interest rate) has a minor impact on the capture cost. Instead, it would be more beneficial to reduce steam requirements. We also provide a surrogate model which can evaluate capture cost from inputs of the gas flow rate, CO2 composition, capture rate, interest rate, steam cost, and electricity cost.

Journal article

Shankar R, Marchesini S, Muller EA, Petit Cet al., 2021, Gas Adsorption in Amorphous Porous Boron Oxynitride: Grand Canonical Monte Carlo Simulations and Experimental Determination

<jats:p>Note: The authors realised errors in the calculations related to this study, which impact the conclusions of the work previously posted.</jats:p>

Journal article

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